Image pickup device and method

ABSTRACT

An imaging apparatus and an imaging method supply an optimum amount of image data to another apparatus. When a PDA has a maximum transfer rate of 1.5 Mbps, a mobile phone determines that the maximum speed of communication with the PDA is low, reduces the amount of moving image data captured by a CCD of the mobile phone accordingly, and supplies the captured moving image data to the PDA. The PDA therefore displays a low-quality moving image on its display unit. When the PDA has a maximum transfer rate of 480 Mbps, the CPU of the mobile phone leaves unchanged the amount of moving picture data captured by the CCD and supplies the captured moving image data to the PDA. The PDA then displays a high-quality moving image on its display unit. The foregoing may be advantageously applied to digital cameras.

BACKGROUND OF THE INVENTION

The present invention relates to an imaging apparatus and an imagingmethod. More specifically, the invention relates to an imaging apparatusand an imaging method for supplying an optimum amount of image data toanother apparatus.

The popularization in recent years of imaging apparatus, such as digitalvideo cameras, has entailed significant improvements in the resolutionof camera equipment, such as the incorporation of a CCD (charge-coupleddevice) in each apparatus. There also is a recent trend toward a growingnumber of feature-rich models of imaging apparatus represented bydigital video cameras furnished with a communication function and mobilephones with an imaging function.

Typically, a digital video camera equipped with a USB (Universal SerialBus) communication function is capable of obtaining moving image dataabout a given object and supplying the moving image data thus acquiredin real time to another apparatus, such as a personal computer, via aUSB cable.

The higher the camera resolution, the greater the amount of moving imagedata obtained by imaging the object. Where a data-receiving destinationapparatus has a low processing capability or where network congestionbetween the sending and the receiving apparatuses are lowering transferrates, the growing data quantity can lead to overflows of communicationprocesses or missing frames in reproduced moving images.

A proposed solution to these problems involves causing the data-sendingdigital video camera to reduce beforehand the amount of outgoing movingimage data, such as by compressing the data, so that moving image datacan be supplied normally to their destination at reduced transfer rates.This solution, however, unnecessarily degrades the quality of reproducedmoving images in cases where high-speed communication is available.

Another proposed solution involves preparing two kinds of data, i.e.,first data, and second data acquired by compressing the first data. Whenthe transfer rate is high the first data is supplied, but the lowerquality second data can be supplied if the transfer rate turns out to below. (For example, refer to Japanese Patent Laid-open No. 2002-99393,pp. 4-12, furnished with FIG. 4.)

The second solution has its own disadvantages. Because the twocategories of data (i.e., first image data, and second image data whichcorrespond to the first in content and which have the smaller quantity)need to be provided in advance, an ever-growing storage area must beallocated to accommodate the data to be supplied. Another disadvantageis that the second solution is not fit for applications where movingimage data about the object are to be supplied in real time.

A further disadvantage is that the compression rate of the preparedsecond image data may or may not be suitable for the ongoing status ofcommunication.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstancesand provides an imaging apparatus and an imaging method for supplying anoptimum amount of image data to another apparatus.

In carrying out the invention and according to one aspect thereof, thereis provided a first imaging apparatus, including imaging means forcapturing image data of an object; transmitting means for transmittingthe captured image data to a communication device via a network; andadjusting means for adjusting an amount of the image data captured bythe imaging means based on a communication speed at which the capturedimage data are transmitted by the transmitting means.

Preferably, the first imaging apparatus may further include a pluralityof units of the transmitting means; and selecting means for selectingany one of the plurality of units of the transmitting means; wherein theadjusting means may adjust the amount of the image data captured by theimaging means based on the communication speed at which the capturedimage data are transmitted by the unit of the transmitting meansselected by the selecting means.

Preferably, the transmitting means further transmits data other than thecaptured image data; and the adjusting means reduces the amount of theimage data captured by the imaging means when the transmitting meanstransmits the other data.

According to another aspect of the invention, there is provided a firstimaging method, including capturing image data of an object;transmitting the captured image data to a communication device via anetwork; and adjusting an amount of the image data captured in thecapturing step based on a communication speed at which the capturedimage data are transmitted in the transmitting step.

Preferably, the first imaging method may further include selecting anyone of a plurality of transmitting units for transmitting the capturedimage data, wherein the transmitting step includes controlling thetransmission so that the captured image data is transmitted by theselected transmission unit; and the adjusting step adjusts the amount ofthe image data captured in the capturing step based on the communicationspeed at which the captured image data are transmitted by the selectedtransmission unit.

Preferably, the transmitting step of the first imaging method furtherincludes transmitting data other than the captured image data; and theadjusting step reduces the amount of the image data captured in thecapturing step when the transmitting step transmits the other data.

According to a further aspect of the invention, there is provided asecond imaging apparatus, including imaging means for capturing imagedata of an object; compressing means for compressing the captured imagedata; transmitting means for transmitting the compressed image data to acommunication device via a network; and adjusting means for adjusting acompression rate for compressing the captured image data based on acommunication speed at which the compressed image data are transmittedby the transmitting means.

Preferably, the second imaging apparatus may further include a pluralityof units of the transmitting means; and selecting means for selectingany one of the plurality of units of the transmitting means; wherein theadjusting means adjusts the compression rate based on the communicationspeed at which the compressed image data are transmitted by the unit ofthe transmitting means selected by the selecting means.

Preferably, the transmitting means of the second imaging apparatusfurther transmits data other than the compressed image data; and theadjusting means raises the compression rate when the transmitting meanstransmits the other data.

According to an even further aspect of the invention, there is provideda second imaging method, including capturing image data of an object;compressing the captured image data; transmitting the compressed imagedata to a communication device via a network; and adjusting acompression rate for compressing the captured image data based on acommunication speed at which the compressed image data are transmittedin the transmitting step.

Preferably, the second imaging method may further include selecting anyone of a plurality of transmitting units for transmitting the compressedimage data, wherein the transmitting step includes controlling thetransmission so that the compressed image data is transmitted by theselected transmission unit; and the adjusting step adjusts thecompression rate based on the communication speed at which thecompressed image data are transmitted by the selected transmission unit.

Preferably, the transmitting step of the second imaging method mayfurther include transmitting data other than the compressed image data,and the adjusting step raises the compression rate when the transmittingstep transmits the other data.

According to a still further aspect of the invention, there is provideda third imaging apparatus, including imaging means for capturing imagedata of an object; compressing means for compressing the captured imagedata; transmitting means for transmitting the compressed image data to acommunication device via a network; and adjusting means for adjusting anamount of the image data captured by the imaging means and a compressionrate for compressing the captured image data based on a communicationspeed at which the compressed image data are transmitted by thetransmitting means.

Preferably, the third imaging apparatus may further include a pluralityof units of the transmitting means; and selecting means for selectingany one of the plurality of units of the transmitting means; wherein theadjusting means adjusts the amount of the image data captured by theimaging means and the compression rate based on the communication speedat which the compressed image data are transmitted by the unit of thetransmitting means selected by the selecting means.

Preferably, the transmitting means of the third imaging apparatusfurther transmits data other than the compressed image data, and theadjusting means reduces the amount of the image data captured by theimaging means while raising the compression rate when the transmittingmeans transmits the other data.

According to a yet further aspect of the invention, there is provided athird imaging method, including capturing image data of an object;compressing the captured image data; transmitting the compressed imagedata to a communication device via a network; and adjusting an amount ofthe image data captured in the capturing step and a compression rate forcompressing the captured image data based on a communication speed atwhich the compressed image data are transmitted in the transmittingstep.

Preferably, the third imaging method may further include selecting anyone of a plurality of transmitting units for transmitting the compressedimage data, wherein the transmitting step includes controlling thetransmission so that the compressed image data is transmitted by theselected transmission unit; and the adjusting step adjusts the amount ofthe image data captured in the capturing step and the compression ratebased on the communication speed at which the compressed image data aretransmitted by the selected transmission unit.

Preferably, the transmitting step of the third imaging method furtherincludes transmitting data other than the compressed image data; and theadjusting step reduces the amount of the image data captured in thecapturing step while raising the compression rate when the transmittingstep transmits the other data.

Where the first imaging apparatus and first imaging method according tothe invention are in use, the image data about a given object arecaptured and transmitted to a communication device via a network. Theamount of the image data captured is adjusted based on the communicationspeed at which the captured image data are transmitted.

Where the second imaging apparatus and second imaging method accordingto the invention are in use, the image data about a given object arecaptured and compressed. The compressed image data are transmitted to acommunication device via a network. The compression rate for compressingthe captured image data is adjusted based on the communication speed atwhich the compressed image data are transmitted.

Where the third imaging apparatus and third imaging method according tothe invention are in use, the image data about a given object arecaptured and compressed. The compressed image data are transmitted to acommunication device via a network. The amount of the image datacaptured and the compression rate for compressing the captured imagedata are adjusted based on the communication speed at which thecompressed image data are transmitted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the basic structure of a mobile phoneequipped with a camera function according to the invention;

FIG. 2 is a schematic view depicting the major internal structure of aCCD in the mobile phone of FIG. 1;

FIG. 3 is a schematic view illustrating typical connections betweenvertical control signals V1 through V8 shown in FIG. 2 on the one hand,and part of vertical shift registers on the other hand;

FIG. 4 is a schematic view indicating how USB-based communicationstypically take place;

FIG. 5 is a block diagram detailing a typical structure of a wirelesscommunication unit in the mobile phone of FIG. 1;

FIG. 6A is a schematic view of a typical system configuration fordisplaying image data acquired by the mobile phone in FIG. 1;

FIG. 6B is a schematic view of another typical system configuration fordisplaying image data acquired by the mobile phone in FIG. 1;

FIG. 7 is a flowchart of steps constituting a mode setting processassociated with the capture of moving image data by the systemconfigurations of FIGS. 6A and 6B;

FIG. 8 is a flowchart of steps constituting an image capture controlprocess;

FIG. 9 is a schematic view sketching how the amount of image data isillustratively reduced;

FIG. 10 is a flowchart of steps constituting an image data compressionprocess;

FIG. 11A is a schematic view of another typical system configuration fordisplaying image data acquired by the mobile phone in FIG. 1;

FIG. 11B is a schematic view of another typical system configuration fordisplaying image data acquired by the mobile phone in FIG. 1;

FIG. 12 is a flowchart of steps constituting a mode setting processapplicable to the system configurations of FIGS. 11A and 11B;

FIG. 13 is a flowchart of steps constituting a process of setting amoving image capture mode based on a request from the party receivingmoving image data;

FIG. 14A is a schematic view of still another typical systemconfiguration for displaying image data acquired by the mobile phone inFIG. 1;

FIG. 14B is a schematic view of still another typical systemconfiguration for displaying image data acquired by the mobile phone inFIG. 1;

FIG. 15 is a flowchart of steps constituting a mode setting processapplicable to the system configurations of FIGS. 14A and 14B;

FIG. 16A is a schematic view of yet another typical system configurationfor displaying image data acquired by the mobile phone in FIG. 1;

FIG. 16B is a schematic view of yet another typical system configurationfor displaying image data acquired by the mobile phone in FIG. 1;

FIG. 17 is a flowchart of steps constituting a process of setting ahigh-quality mode in which to capture still image data based on arequest from a PDA in the system configurations of FIGS. 16A and 16B;

FIG. 18 is a flowchart of steps constituting a mode setting processassociated with the transfer of still image data in the systemconfigurations of FIGS. 16A and 16B;

FIG. 19 is a schematic view of yet another typical system configurationfor displaying image data acquired by the mobile phone in FIG. 1;

FIG. 20 is a timing chart outlining typical flows of processing byindividual devices in the system configuration of FIG. 19;

FIG. 21 is a block diagram depicting a typical structure of a CMOSsensor; and

FIG. 22 is a schematic view showing how the amount of image data isreduced using the CMOS sensor of FIG. 21.

DETAILED DESCRIPTION

FIG. 1 is a block diagram showing the basic structure of a mobile phoneequipped with a camera function according to the invention.

Light from an object, not shown, enters a CCD (charge-coupled device) 12through a lens unit 11 of the mobile phone 1 that includes lenses and aniris mechanism. The entered light is subjected to a photoelectricconversion process.

A video signal output by the CCD 12 is supplied to a CDS (correlateddouble sampling) circuit 13. This circuit removes noise components fromthe input signal by submitting the signal to a correlated doublesampling process. The signal thus processed is output to an AGC(automatic gain control) circuit 14. The AGC circuit 14 controls thegain of the input signal before outputting the controlled signal to anA/D (analog/digital) converter 15. The A/D converter 15 converts theinput analog signal to a digital signal that is output to a DSP (digitalsignal processor) 16.

The DSP 16 generates control signals such as AF (auto focus), AE (autoexposure) and AWB (auto white balance) using an incorporated imageadjustment processing unit 21, and sends the generated control signalsto a CPU (central processing unit) 31 through a bus 30. The DSP 16 alsocompresses or expands an input image signal using an internal imagecompression/expansion processing unit 22. During a compression/expansionprocess, the image compression/expansion processing unit 22 places thevideo signal temporarily in an SDRAM (synchronous dynamic random accessmemory) 17 under control of an SDRAM controller 23 incorporated in theDSP 16.

The image data compressed by the image compression/expansion processingunit 22 are fed to a RAM (random access memory) 33 or elsewhere via thebus 30.

The CPU 31 controls component units of the mobile phone and performsvarious processes in keeping with programs that are held in a ROM (readonly memory) 32 or loaded from a storage unit 35 into the RAM 33. TheRAM 33 may also accommodate data required by the CPU 31 in carrying outdiverse processes.

The CPU 31 is also connected to an external operation input unit 34 thatmay be operated by a user. The external operation input unit 34 is madeup of buttons, such as a shutter button and a menu button, and othercontrols including dials, knobs, and a touch-sensitive panel (noneshown). When operated by the user, the external operation input unit 34receives various instructions from the user and supplies instructioninformation to the CPU 31. Given the instruction information, the CPU 31performs various processes accordingly.

The CPU 31, ROM 32, and RAM 33 are interconnected via the bus 30. Thebus 30 is further connected to: a flash memory 35 composedillustratively of a nonvolatile semiconductor memory; a display controlunit 36 that controls images to be displayed on an LCD 37; a memoryinterface 38 to which a memory card 39 or the like is attached; a USB(universal serial bus) controller 40 for controlling a USB connector 41to which a USB cable, not shown, is connected; and a wirelesscommunication unit 42 that transmits the image data captured by the CCD12 wirelessly to another apparatus under control of the CPU 31.

The display control unit 36 incorporates a VRAM (video random accessmemory), not shown. The display control unit 36 stores the image datacaptured by the CCD 12 in the internal VRAM, and causes the LCD 37 todisplay images corresponding to the image data thus held in the VRAM orin other memories (e.g., RAM 33, flash memory 35, or memory card 39connected to the memory interface 38).

A drive 43 is connected as needed to the bus 30 via an interface, notshown. Computer programs are retrieved from a magnetic disc 44, anoptical disc 45, a magneto-optical disc 46 or a semiconductor memory 47loaded in the drive 43 and are installed into the RAM 33 or flash memory35. Computer programs may also be retrieved from the memory card 39attached as needed to the memory interface 38 and installed into the RAM33 or flash memory 35.

The CPU 31 receives instruction information from the user through theexternal operation input unit 34, control information from the imageadjustment processing unit 21, or information derived from the executionof various programs. Based on the received information, the CPU 31controls the operations of the CDS circuit 13, AGC circuit 14, and A/Dconverter 15.

A method by which to transmit acquired image data to another apparatusis selected according to the instructions input by the user through theexternal operation input unit 34. More specifically, by operating theexternal operation input unit 34 in the setup of FIG. 1, the user maydetermine at will whether the image data are to be transmitted throughthe USB connector 41 or through the wireless communication unit 42.Based on the communication method thus selected, the CPU 31 controls aTG (timing generator) 51 for regulating the operation of the CCD 12 inorder to control the amount of image data captured by the CCD 12. TheCPU 31 also controls the rate at which the image data are compressed bythe DSP 16 in accordance with the selected communication method.

The CPU 31 controls the TG 51 for regulating the operation of the CCD 12based on either a communication speed for wired communication by the USBcontroller 40, a communication speed for wireless communication by thewireless communication unit 42, a request from the apparatus the mobilephone 1 is communicating with, or instructions input through theexternal operation input unit 34. In so doing, the CPU 31 controls theamount of image data captured by the CCD 12, the compression rate for acompression process by the image compression/expansion processing unit22 compressing the image data, and the amount of image data to betransmitted.

Furthermore, the CPU 31 controls an iris shutter driver 53 forregulating the operation of the lens unit 11, thereby adjusting theshutter speed and regulating the iris mechanism.

The TG 51 and a V driver 52 are connected to the CCD 12. Linked via aserial control bus to the CPU 31 and controlled thereby, the TG 51 and Vdriver 52 control the workings of the CCD 12.

Specifically, based on control signals from the CPU 31, the TG 51generates various control signals including a horizontal clock signalfor driving a horizontal shift register 63 of the CCD 12, to bedescribed later with reference to FIG. 2. The generated control signalsare fed to the CCD 12 and V driver 52.

In keeping with the control signals from the TG 51, the V driver 52generates vertical control signals V1 through V8 for driving verticalshift registers 62-1 through 62-n of the CCD 12, to be discussed laterwith reference to FIG. 2. The vertical control signals generated by theV driver 52 (i.e., a vertical register driver) are supplied to the CCD12.

FIG. 2 is a schematic view depicting the major internal structure of theCCD 12.

As shown in FIG. 2, the CCD 12 has photodiodes 61-1-1 through 61-n-marranged in m rows and n columns. The n columns of the photodiodes61-1-1 through 61-n-m are connected to the vertical shift registers 62-1through 62-n respectively.

In the description that follows, the photodiodes 61-1-1 through 61-n-mwill be generically referred to as the photodiode 61 if there is nospecific need to distinguish the individual photodiodes. Likewise thevertical shift registers 62-1 through 62-n will be simply referred to asthe vertical shift register 62 where there is no need to distinguish theindividual vertical shift registers.

The photodiodes 61-1-1 through 61-1-m in the leftmost column areconnected to the vertical shift register 62-1; the photodiodes 61-2-1through 61-2-m in the second column from left are connected to thevertical shift register 62-2; and so on. The photodiodes 61-n-1 through61-n-m in the n-th column are connected to the vertical shift register62-n.

The vertical shift register 62-1 includes a plurality of registerscapable of retaining electrical charges accumulated in the photodiodes61-1-1 through 61-1-m connected to the registers, respectively. Thevertical shift register 62-1, linked to the horizontal shift register63, shifts the retained electrical charges one place at a time and hasthe shifted charges supplied to the horizontal shift register 63.

The CCD 12 is supplied with vertical control signals V1 through V8 fromthe V driver 52. As will be discussed later with reference to FIG. 3,the individual registers in the vertical shift register 62-1 are eachsupplied with one of the vertical control signals V1 through V8. Undercontrol of the vertical control signals V1 through V8, the verticalshift register 62-1 retains and shifts the above-mentioned electricalcharges.

A substrate voltage is applied to the CCD 12 in the form of a SUB(substrate) signal from the V driver 52. The signal causes theelectrical charges accumulated in those of the photodiodes 61-1-1through 61-1-m which are designated by the vertical control signals V1,V3, V5 and V7 to be transferred to the vertical shift register 62-1. Thetransferred electrical charges are shifted one place at a time, downwardas viewed in FIG. 2, under control of the vertical control signals V1through V8 so that the charges are transferred successively to thehorizontal shift register 63.

Each of the vertical shift registers 62-2 through 62-n has the samestructure as the vertical shift register 62-1 and operates in the samemanner as the latter. Thus, the remaining vertical shift registers willnot be discussed further in structure or in operation.

FIG. 3 is a schematic view illustrating typical connections between thevertical control signals V1 through V8 on the one hand, and part of thevertical shift register 62 on the other hand.

As shown in FIG. 3, every second register making up the vertical shiftregister 62 is connected to the photodiode 61. Each register coupledwith the photodiode is connected to the vertical control signals V1, V3,V5 or V7. The other registers are each linked to the vertical controlsignals V2, V4, V6 or V8.

For example, when the vertical control signals V1, V3, V5 and V7 areinput to the vertical shift register 62, the electrical chargesaccumulated in all the photodiodes 61 are transferred to the verticalshift register 62.

In another example, when the vertical control signals V5 and V7 aloneare input to the vertical shift register 62, only the electrical chargesin those photodiodes 61 (designated by reference character A in FIG. 3)to which the signals V5 and V7 are input are transferred to the verticalshift register 62. The electrical charges in the photodiodes 61designated by reference character B in FIG. 3 are discharged, nottransferred. In this case, the electrical charge from one out of everyfive individual registers is captured.

Returning to FIG. 2, the horizontal shift register 63 is made up of aplurality of registers each retaining an electrical charge of onephotodiode from each of the vertical shift registers 62-1 through 62-nconnected to the registers, respectively. In the horizontal shiftregister 63, the retained electrical charges are shifted one place at atime before being sent successively out of the CCD 12.

Each individual register in the horizontal shift register 63 isconnected to a discharge drain and to a column selection discharge gatefor determining whether to discharge electrical charges through thatdischarge drain (none shown). The gates permit selection of theelectrical charges to be transferred out of the CCD 12.

When an RG signal fed by the TG 51 causes a voltage to be fed to a givencolumn selection discharge gate, only the electrical charge of thecolumn associated with the discharge drain linked to the voltage-fedcolumn selection discharge gate is selectively discharged. The otherelectrical charges are shifted left one place (as viewed in FIG. 2)under control of horizontal control signals (H1 and H2) coming from theTG 51, so that the charges are transferred successively out of the CCD12.

In the manner described above, the CPU 31 causes the TG 51 to controlthe CCD 12 so as to regulate the amount of image data to be captured.

FIG. 4 is a schematic view indicating how USB-based communicationstypically take place.

A USB-based communication setup involves two communicating terminals: ahost that controls the communication, and a device that communicateswith the host.

On the host side, client software 71 executed by the CPU 31 in FIG. 1 orthe like gives a communication instruction to USB system software 72executed by the USB controller 40 in FIG. 1. In turn, the USB systemsoftware 72 controls communications carried out through a USB businterface 73 which is a physical interface.

On the device side, a function 74 (specific to the device) gives acommunication instruction to a USB logical device 75. In turn, the USBlogical device 75 controls communications through a USB bus interface76, a physical interface.

The client software 71 and function 74 carry out relevant processestherebetween based on information exchanged in a USB-basedcommunication. The USB system software 72 and USB logical device 75control the USB-based communication so as to exchange requestedinformation through the USB bus interfaces 73 and 76.

The USB controller 40 in FIG. 1 is compatible with USB version 2.0(i.e., a communication standard) and capable of communicating attransfer rates of up to 480 Mbps. If the communicating device connectedto the USB connector 41 via a USB cable is a device compatible with USBversion 1.1 and capable of communicating at transfer rates of up to 12Mbps or up to 1.5 Mbps, the USB controller 40 also accommodates thatdevice operating at a reduced transfer rate. Information about theongoing communication is supplied to the CPU 31. Given the communicationinformation, the CPU 31 controls accordingly the amount of image datacaptured by the CCD 12 as well as a compression rate used in acompression process on the image data.

Furthermore, the USB controller 40 measures an actual transfer rate thatmay vary under changing loads in a manner to be described later, andsupplies information about the measurements to the CPU 31. Based on themeasurement information received, the CPU 31 controls the amount ofimage data captured by the CCD 12 and the compression rate for the imagedata.

FIG. 5 is a block diagram detailing a typical structure of the wirelesscommunication unit 42 included in FIG. 1.

In this structure, an antenna 81 receives radio waves from anotherdevice and supplies the received signal to a selector 82. The antenna 81also transmits signals from the selector 82 to the other device usingradio waves. The selector 82 demodulates the signal received from theantenna 81, such as through CDMA (code division multiple access)arrangements, and sends the demodulated signal to a down converter 83.

The down converter 83 converts the carrier frequency of the demodulatedsignal thus acquired to a low frequency before forwarding thedemodulated signal to a receiving interface 84. The receiving interface84 subjects the acquired demodulated signal to an A/D conversionprocess, for example, for conversion to digital form. The resultingdigital signal is sent to a base band signal processing unit 85.

From the digital signal sent by the receiving interface 84, the baseband signal processing unit 85 extracts received data through packetfiltering, error signal handling and other processes in accordance withsuitable criteria. The received data thus extracted are placed onto thebus 30. The base band signal processing unit 85 also acquires data viathe bus 30, supplements the acquired data with control signals or thelike, and forwards the supplemented data to a transmitting interface 86.The transmitting interface 86 converts the acquired digital signal to ananalog signal and feeds the resulting analog signal to a power amplifier87. The power amplifier 87 amplifies the received signal into anoutgoing signal and sends the amplified signal via the selector 82 tothe antenna 81 for output.

The maximum communication speed for the wireless communication unit 42may vary depending on the carrier in use and/or the communicationstandards in effect.

The wireless communication unit 42 varies its transfer rate so as toaccommodate the maximum communication speed of the opposite devicecommunicating with the unit 42. Information about the changed transferrate is supplied to the CPU 31. Based on the supplied information, theCPU 31 controls the amount of image data captured by the CCD 12 and therate at which the image data are compressed.

In addition, the wireless communication unit 42 measures the ongoingtransfer rate varying with different loads in a manner to be describedlater, and feeds information about the measurements to the CPU 31. Inkeeping with the supplied information, the CPU 31 controls the amount ofimage data captured by the CCD 12 and the compression rate for the imagedata.

What follows is a description of how the CPU 31 controls the amount ofimage data captured by the CCD 12 in accordance with the maximumcommunication speed of the opposite communication device connected viathe USB connector 41. FIGS. 6A and 6B are schematic views of systemconfigurations in which the image data acquired by the mobile phone 1 inFIG. 1 are transferred through a USB cable to another device fordisplay.

In FIG. 6A, the mobile phone 1 is connected to a PDA (personal digitalassistant) 91 via a USB cable 92 connected to the USB connector 41furnished at the bottom of the phone. Incident light entering the CCD 12through the lens unit 11 at the top left corner (as viewed in FIG. 6A)of the mobile phone 1 is subjected to photoelectric conversion, wherebymoving image data are acquired. Under control of the CPU 31, a movingimage corresponding to the acquired moving image data appears on the LCD37 at the top front of the mobile phone 1 while being suppliedconcurrently to the PDA 91 through the USB cable 92. The supplied movingimage is displayed on a display unit at the front of the PDA 91.

Alternatively, the lens unit 11, LCD 37, and USB connector 41 may belocated elsewhere on the mobile phone 1.

If the maximum transfer rate for the PDA 91 in the system configurationof FIG. 6A is assumed to be 1.5 Mbps, then the maximum speed ofcommunication between the mobile phone 1 and the PDA 91 is 1.5 Mbps aswell. In other words, even if the mobile phone 1 has a communicationfacility capable of communicating at a maximum communication speed of480 Mbps, the maximum speed of communication between the phone 1 and thePDA 91 is brought down to that of the PDA 91.

When the CPU 31 of the mobile phone 1 determines that the maximum speedof communication with the PDA 91 is very low, the CPU 31 causes the CCD12 to capture lesser quantities of moving image data than before, andtransfers the reduced amount of captured moving image data to the PDA91. This causes the display unit of the PDA 91 to display a low-qualitymoving image 93. That is, the CPU 31 causes the CCD 12 to reduce theamount of image data it captures to a level where the USB controller 40can normally transmit the data at a maximum communication speed that thePDA 91 is capable of. In this manner, the mobile phone 1 supplies movingpicture data to the PDA 1 without data overflows or missing framestaking place in a USB-based communication setup at the maximum transferrate of 1.5 Mbps.

Where the PDA 91 has the maximum transfer rate of 480 Mbps as shown inFIG. 6B, i.e., where large quantities of image data can be normallytransmitted thereto, the CPU 31 allows the CCD 12 not to reduce theamount of moving image data it captures, and supplies the capturedmoving image data to the PDA 91. This causes the display unit of the PDA91 to display a high-quality moving image 94.

In the manner described, the CPU 31 causes the CCD 12 to control theamount of moving image data it captures in keeping with the processingcapability of the destination device to which the moving image data aresupplied.

More specifically, the CPU 31 acquires information about the destinationdevice through the USB controller 40, selects an image quality modebased on the acquired information, causes the CCD 12 and related partsto acquire moving image data in controlled quantities, and supplies themoving image data to the PDA 91 through the USB cable 92.

Described below with reference to the flowchart of FIG. 7 is a typicalmode setting process associated with the capture of moving image data bythe CPU 31 in the system configurations of FIGS. 6A and 6B.

An imaging process is started, for example, by the user's instruction.In step S1, the CPU 31 initially requests from the USB controller 40device information about the PDA 91, including its capability totransfer moving image data, and determines whether the requested deviceinformation has been acquired from the USB controller 40.

If in step S1 the device information has been acquired from the USBcontroller 40, the process goes to step S2. In step S2, the CPU 31selectively sets one of two predetermined modes associated with thecapture of moving image data by the CCD 12. One of the two modes is ahigh-quality mode in which a predetermined amount of image data istransferred, and the other is a low-quality mode in which a reducedamount of image data is transferred. After setting the mode, the processreaches step S3.

If in step S1 the device information has not been acquired, the processskips step S2 and goes directly to step S3.

In step S3, the CPU 31 determines whether the mode setting process isready to be terminated. If the mode setting process is not ready to beterminated, the process returns to step S1 and the subsequent steps arerepeated.

If in step S3 the mode setting process is ready to be terminated, theprocess goes to step S4, and a termination process is performed toterminate the mode setting process.

After the CPU 31 has established the mode related to the capture ofmoving image data as described above, the CPU 31 proceeds to carry outan image capture control process. How this process is performed isdescribed below with reference to the flowchart of FIG. 8.

In step S21, the CPU 31 determines whether the high-quality mode iscurrently set in connection with the capture of moving image data. Ifthe high-quality mode is in effect, the process goes to step S22. Instep S22, the CPU 31 causes the CCD 12 and TG 51 in FIG. 1 to captureimage signals of all pixels in order to generate high-quality movingimage data.

When a first field of a moving image is to be extracted in thehigh-quality mode, the electrical charges accumulated in the photodiodes61 corresponding to the vertical control signals V3 and V7 in FIG. 3 aretransferred to the vertical shift register 62; when a second field ofthe moving image data is to be extracted, the electrical charges held inthe photodiodes 61 corresponding to the vertical control signals V1 andV5 are transferred to the vertical shift register 62; and so on. The CPU31 thus controls the TG 51 in a manner causing the CCD 12 to capture theelectrical charges of all photodiodes 61 so as to output one frame ofmoving image data.

After the processing of step S22 is completed, the process goes to stepS24.

If in step S21 the mode currently associated with the capture of movingimage data is not the high-quality mode (i.e., when the low-quality modeis set), then the process goes to step S23. In step S23, the CPU 31causes the CCD 12 and TG 51 to capture the image signals of part of thepixels in order to generate low-quality moving image data.

When one frame of electrical charges is to be extracted in thelow-quality mode, only the electrical charges accumulated in thephotodiodes 61 corresponding to the vertical control signals V5 and V7in FIG. 3 (i.e., photodiodes 61 designated by reference character A inFIG. 3) are transferred to the vertical shift register 62. This processreduces the amount of data in the vertical direction by four-fifths, asillustrated in FIG. 9.

The CCD 12 utilizes a primary color filter arrangement having red (R),green (G) and blue (B) filters laid out in the Bayer pattern to captureincident light. As shown in FIG. 9, the photodiodes are arranged in twotypes of horizontal rows alternating in the vertical direction. In onetype of row, the photodiodes from which to extract electrical chargescorresponding to the G signal are positioned side by side with thephotodiodes from which to extract electrical charges corresponding tothe B signal. In the other type of row, the photodiodes from which toextract electrical charges corresponding to the R signal are positionedside by side with the photodiodes from which to extract electricalcharges corresponding to the G signal.

More specifically, in the first row at the top of FIG. 9, thephotodiodes from which to extract electrical charges corresponding tothe G signal are arranged side by side with the photodiodes from whichto extract electrical charges corresponding to the B signal. In thesecond row from the top, the photodiodes from which to extractelectrical charges corresponding to the R signal are laid out side byside with the photodiodes from which to extract electrical chargescorresponding to the G signal.

In the low-quality mode, of the photodiodes 61 arranged as describedabove, those in the rows designated by reference character A in FIG. 9have their electrical charges captured. This reduces the amount of datain the vertical direction by four-fifths.

The electrical charges transferred to the vertical shift registers 62are shifted one place at a time to the horizontal shift register 63 asdescribed above. Under control of the RG signal fed from the TG 51 tothe CCD 12, the horizontal shift register 63 discharges the electricalcharges other than those of relevant columns. For example, under controlof the RG signal, the horizontal shift register 63 retains theelectrical charges of every fifth column while discharging those of theremaining four columns through the drains. Getting the horizontal shiftregister 63 to operate in this manner reduces the amount of datacaptured in the horizontal direction by four-fifths.

In the manner described, the CPU 31 causes the CCD 12 to capture theelectrical charges of part of its photodiodes in order to generate oneframe of moving image data.

Returning to FIG. 8, the CPU 31 completes the process of step S23 beforereaching step S24.

In step S24, the CPU 31 determines whether the image capture controlprocess is ready to be terminated. If the process is not ready to beterminated, the process returns to step S21 and the subsequent steps arerepeated.

If in step S24 the image capture control process is ready to beterminated, for example, based on the user's input, the process goes tostep S25. In step S25, the CPU 31 performs a termination process toterminate this image capture control process.

The moving image data captured as described above are sent by the CPU 31to the USB controller 40 or related components. From there, the data arefed to the PDA 91 through the USB cable 92. In this manner, the mobilephone 1 supplies moving image data to the PDA 91 without incurring dataoverflows or missing frames. It should be noted that signals may be readfrom the photodiodes 61 in any other manner than what was describedabove provided the amount of retrieved electrical charges is suitablycontrolled in keeping with the image quality mode in effect.

The CPU 31 may compress the captured moving image data before supplyingthe data to the PDA 91. In this case, the compression rate may be variedwith the ongoing communication speed, i.e., depending on the currentmode in which moving picture data are captured. At this point, theamount of electrical charges read from the CCD 12 will not be changed inaccordance with the image quality mode in effect as discussed above.

Described below with reference to the flowchart of FIG. 10 is a typicalimage data compression process carried out by the CPU 31.

In step S41, the CPU 31 determines whether the high-quality mode iscurrently in effect. If the high-quality mode has been established, theprocess moves to step S42. In step S42, the CPU 31 compresses movingimage data at a first compression rate for high-quality image datacompression. Step S42 is followed by step S44.

If in step S41 the high-quality mode has not been established (i.e., thelow-quality mode is in effect), the process goes to step S43. In stepS43, the CPU 31 compresses the moving image data at a second compressionrate (which is higher than the first rate) for low-quality image datacompression. Step S43 is followed by step S44.

In step S44, the CPU 31 determines whether the image data compressionprocess is ready to be terminated. If the process is not ready to beterminated, the process returns to step S41 and the subsequent steps arerepeated.

If in step S44 the image data compression process is ready to beterminated for some reason, the process goes to step S45. In step S45,the CPU 31 performs a termination process to terminate the image datacompression process.

In the manner described, the CPU 31 compresses the captured moving imagedata at a compression rate commensurate with the currently establishedmode in which the moving picture data are captured (i.e., moving imagecapture mode), and supplies the compressed data to the USB controller 40or related components. From there, the compressed data are sent to thePDA 91 through the USB cable 92. In this manner, the mobile phone 1 cansupply moving image data to the PDA 91 without incurring data overflowsor missing frames.

There can be other variations of this invention each diversely combiningthe embodiments described above. In a commonly conceived variation, theamount of electrical charges read from the CCD 12 in the high-qualitymode (where high-speed data transfer is available) may be raised forlower data compression, and the amount of electrical charges read fromthe CCD 12 in the low-quality mode (where low-speed data transfer aloneis feasible) may be reduced for higher data compression. In anothervariation where priority is given to the compression process, the amountof electrical charges read from the CCD 12 in the high-quality mode (forhigh-speed data transfer) may be reduced for lower data compression, andthe amount of electrical charges retrieved from the CCD 12 in thelow-quality mode (only for low-speed data transfer) may be raised forhigher data compression.

The foregoing description has focused on how to change the moving imagecapture mode in accordance with the communication speed of the PDA 91,the destination to which the moving image data are transmitted. Wherethe mobile phone 1 and PDA 91 are connected via a network 101, such as aLAN (local area network) or the Internet as shown in FIGS. 11A and 11B,the moving image capture mode may be controlled in keeping with thebandwidth and traffic status of the network 101. The network trafficstatus may be determined, for example, upon initial establishment ofconnection between the devices involved. More specifically, a signal isissued from one of the connected devices to the other to find out whothe other party is and how capable the opposite device is incommunication. At this point, the traffic status may be determined bymeasuring how long it takes to receive a response signal from the otherparty responding to the issued signal.

For example, where the network 101A a is a broadband network as shown inFIG. 11A or is not congested, i.e., where high-speed communication isavailable, the CPU 31 of the mobile phone 1 sets the high-quality modeas the moving image capture mode to generate high-quality moving imagedata, and supplies the generated data to the PDA 91. In turn, the PDA 91displays on its display unit a high-quality moving image 94corresponding to the high-quality moving image data acquired.

In another example, where the network 101B is a narrowband network asshown in FIG. 11B or is congested, i.e., where high-speed communicationis unavailable, the CPU 31 of the mobile phone 1 sets the low-qualitymode as the moving image capture mode to generate low-quality movingimage data in reduced quantities, and supplies the generated data to thePDA 91. In turn, the PDA 91 displays on its display unit a low-qualitymoving image 93 corresponding to the low-quality moving image dataacquired.

Described below with reference to the flowchart of FIG. 12 is a typicalmode setting process to be carried out in the case outlined above.

Initially, the CPU 31 causes the USB controller 40 to generatecommunication information including the current communication speed andacquires that information via the bus 30. In step S61, the CPU 31determines whether the communication information has been acquired. Ifthe communication information has been acquired, the process proceeds tostep S62. In step S62, the CPU 31 establishes an appropriate movingimage capture mode based on the acquired communication information. StepS62 is followed by step S63.

If in step S61 the communication information has not been acquired, theCPU 31 skips step S62 and goes directly to step S63.

In step S63, the CPU 31 determines whether the mode setting process isready to be terminated. If the process is not ready to be terminated,the process returns to step S61 and the subsequent steps are repeated.

If in step S63 the mode setting process is ready to be terminated, forexample, based on the user's instructions, step S64 is reached. In stepS64, the CPU 31 performs a termination process to terminate the modesetting process.

In the manner described above, the CPU 31 can establish a moving imagecapture mode commensurate with the current communication speed of theUSB controller 40. In keeping with changes in the traffic status of thenetwork 101 between the mobile phone 1 and the PDA 91 to which movingimage data are sent, the CPU 31 can continuously supply normal movingimage data to the PDA 91 for the display of a moving image reflectingthe supplied data without incurring data overflows or missing frames.

In the examples above, the network 101 was shown intervening between themobile phone 1 that supplies moving image data on the one hand and thePDA 91 that acquires the moving image data on the other hand. However,the invention is not limited to this setup. Any suitable communicationequipment such as repeaters may be arranged to intervene between themobile phone 1 and the PDA 91.

As another alternative, it is possible for the CPU 31 to establish asuitable moving image capture mode based on instructions from the PDA 91to which moving image data are to be supplied.

Described below with reference to the flowchart of FIG. 13 is how themode setting process is typically performed where a moving image capturemode is established on the basis of a request from the party thatreceives the moving image data.

In step S81, the CPU 31 determines through the USB controller 40 whetheran image quality designation request has been acquired from the PDA 91.If the request has been acquired, the process proceeds to step S82. Instep S82, the CPU 31 updates the setting of the moving image capturemode in accordance with the acquired image quality designation request.Step S82 is followed by step S83.

If in step S81 the image quality designation request has not beenacquired from the PDA 91, the CPU 31 skips step S82 and goes directly tostep S83.

In step S83, the CPU 31 determines through the USB controller 40 whethera designation cancel request has been acquired from the PDA 91. If thedesignation cancel request has been acquired, the process proceeds tostep S84. In step S84, the CPU 31 restores the initial mode settingupdated in step S82. Step S84 is followed by step S85.

If in step S83 the designation cancel request has not been acquired, theCPU 31 skips step S84 and goes directly to step S85.

In step S85, the CPU 31 determines whether the mode setting process isready to be terminated. If the process is not ready to be terminated,the process returns to step S81 and the subsequent steps are repeated.

If in step S85 the mode setting process is ready to be terminated, forexample, based on the user's instructions, the process goes to step S86.In step S86, the CPU 31 performs a termination process to terminate themode setting process.

That is, if the CPU 31 acquires an image quality destination requestfrom the PDA 91, the destination to which moving image data is to besupplied, then the CPU 31 uses the requested mode unless and until adesignation cancel request is received. The acquired request is givenpriority over any other conditions for determining the mode setting.Once the designation cancel request is acquired, the CPU 31 restores theinitial mode setting in effect before the image quality designationrequest was acquired.

In the manner described above, the CPU 31 can establish the moving imagecapture mode based on the request from the PDA 91. This makes itpossible, for example, for the user of the PDA 91 to designate a desiredmoving image quality while viewing the actual moving image displayed onthe display unit.

It is possible for the mobile phone 1 to exchange moving image datawirelessly with another mobile phone using the wireless communicationunit 42 as depicted in FIG. 14A, or to supply moving image data to thePDA 91 connected with the USB connector 41 as shown in FIG. 14B. In thesetup of FIG. 14A where the wireless communication unit 42 is utilizedfor wireless communication, the maximum communication speed is 9,600bps; in the setup of FIG. 14B where the USB controller 40 is employedfor wired communication, the maximum communication speed is 480 Mbps.

As described, the communication speed may vary depending on whichcommunication device is being used. The CPU 31 may thus set the mode inaccordance with the communication device utilized to supply moving imagedata.

The setup of FIG. 14A, for example, involves mobile phones 1A and 1Beach having the same structure as that of the mobile phone 1 andoperating in the same manner as the latter. In the setup, incident lightentering the lens unit 11 at the top left corner of the mobile phone 1Ais subjected to photoelectric conversion by the CCD 12 therein, wherebymoving image data are obtained. The data thus acquired are supplied fromthe mobile phone 1A to the mobile phone 1B in a wireless communicationat communication speeds of up to 9,600 bps. In this case, the CPU 31 ofthe mobile phone 1A sets the low-quality mode for the capture of movingimage data.

When small quantities of moving image data are captured in thelow-quality mode thus established, the CPU 31 of the mobile phone 1Acauses a low-quality moving image corresponding to the captured movingimage to appear on the display 37 at the front of the phone 1A, andforwards the moving image data to the wireless communication unit 42.From there, the moving image data are transferred to the mobile phone 1Bvia the antenna 81 at the top right corner of the mobile phone 1A.

The CPU 31 of the mobile phone 1B acquires the transmitted moving imagedata through the antenna 81 at the top right corner of the phone 1B, anddisplays a low-quality moving image 93 corresponding to the acquireddata on the display 37 at the front of the phone 1B.

In the setup of FIG. 14B, incident light entering the lens unit 11 atthe top left corner of the mobile phone 1 is subjected to photoelectricconversion by the CCD 12 therein, whereby moving image data areobtained. The data thus acquired are supplied from the mobile phone 1 tothe PDA 91 in a USB-based communication at communication speeds of up to480 Mbps. In this case, the CPU 31 of the mobile phone 1 sets thehigh-quality mode for the capture of moving image data.

When small quantities of moving image data are captured in thehigh-quality mode thus established, the CPU 31 of the mobile phone 1causes a high-quality moving image corresponding to the captured movingimage to appear on the display 37 at the front of the phone 1, andsupplies the data to the USB controller 40. From there, the moving imagedata are transferred to the PDA 91 through the USB cable 92 connectedwith the USB connector 41 furnished at the bottom of the phone 1.

Upon acquiring the moving image data, the PDA 91 causes its display unitto display a high-quality moving image 94 corresponding to the acquireddata.

Described below with reference to the flowchart of FIG. 15 is a typicalmode setting process to be carried out in the case outlined above.

Initially, the CPU 31 in step S101 controls the USB controller 40 andwireless communication unit 42 to acquire therefrom information abouttheir communication capabilities, and determines whether thecommunication device to be used is capable of high-speed communication.If the communication device is capable of high-speed communication, theprocess goes to step S102 and the high-quality mode is set. The CPU 31then terminates the mode setting process. If in step S101 thecommunication device is found to be incapable of high-speedcommunication, the process proceeds to step S103 to establish thelow-quality mode, before terminating the mode setting process.

In the manner described above, the CPU 31 sets the appropriate mode forthe capture of moving image data in accordance with the capability ofthe communication device to be used.

Alternatively, as shown in FIG. 16A, the CPU 31 may cause the CCD 12 tocapture still images of a predetermined level of quality on the basis ofrequests from the PDA 91 that seeks to acquire moving image data. Insuch a case, there is no need to transfer still images in real-time.That means large quantities of still image data can be transferrednormally. For that reason, the still images may be captured in apredetermined mode regardless of the currently established mode for thecapture of moving image data. For example, where moving image data areto be transferred in the low-quality mode, still images of high qualitycan be captured if the still image capture mode is set for high qualityon the mobile phone 1.

Described below with reference to the flowchart of FIG. 17 is how themode setting process is performed when a still image is captured in thehigh-quality mode on the basis of a request from the PDA 91.

Initially, the CPU 31 in step S121 determines through the USB controller40 whether a still image capture instruction has been acquired. The CPU31 waits until the still image capture instruction is acquired.

When the still image capture instruction has been acquired, the processgoes to step S122. In step S122, the CPU 31 establishes the high-qualitymode. In step S123, the CPU 31 determines through the CCD 12 whetherstill image data have been acquired. The CPU 31 waits until the stillimage data are acquired.

When the CCD 12 has captured a still image and thereby acquired thestill image data, the process goes to step S124. In step S124, the CPU31 restores the initial mode setting, terminates the still image captureprocess, and resumes acquiring moving image data.

In step S125, the CPU 31 determines whether the mode setting process isready to be terminated. If the mode setting process is not ready to beterminated, the process returns to step S121 and the subsequent stepsare repeated.

If in step S125 the mode setting process is ready to be terminated, theprocess goes to step S126. In step S126, the CPU 31 performs atermination process to terminate the mode setting process.

In the manner described, the CPU 31 can acquire still image datarepresenting a high-quality still image based on the request from thePDA 91 regardless of the currently established mode for the capture ofmoving image data.

The acquired still image data may be supplied to the PDA 91 based on thelatter's request as shown in FIG. 16B. This allows a corresponding stillimage 111 to be displayed on the display unit of the PDA 91. Because themaximum transfer rate for moving image data drops during the transfer ofstill image data, the CPU 31 of the mobile phone 1 switches to thelow-quality mode for the capture of moving image data. At this point,the display unit of the PDA 91 displays a low-quality moving image 93along with the high-quality still image 111 having been captured. Afterall the still image data have been transferred, the CPU 31 restores theinitial mode setting for the capture of moving image data.

Described below with reference to the flowchart of FIG. 18 is how themode setting process is carried out for the transfer of still imagedata.

Initially, the CPU 31 in step S141 determines whether a still imagetransfer instruction has been acquired. The CPU 31 waits until the stillimage transfer instruction is acquired. When the still image transferinstruction has been acquired, the process goes to step S142. In stepS142, the CPU 31 sets the low-quality mode for the capture of movingimage data, and causes the USB controller 40 to start transferring stillimage data.

In step S143, the CPU 31 determines whether the still image transferprocess has ended. The CPU 31 waits until the still image transferprocess is brought to an end. When the still image transfer process hasended, the process goes to step S144. In step S144, the CPU 31 restoresthe initial mode setting thus replacing the low-quality mode that hadbeen set for the capture of moving image data.

In step S145, the CPU 31 determines whether the mode setting process isready to be terminated. If the mode setting process is not ready to beterminated, the process returns to step S141 and the subsequent stepsare repeated. If in step S145 the mode setting process is ready to beterminated, the process goes to step S146. In step S146, the CPU 31performs a termination process to terminate the mode setting process.

In the manner described above, the CPU 31 of the mobile phone 1 cancapture still images based on a request from the PDA 91 and supply thestill image data to the latter.

The communication device connected to the mobile phone 1 may be somedevice other than the PDA 91. For example, as shown in FIG. 19, twomobile phones (1A and 1B) and a PDA 91 may be interconnected via anetwork 120, such as a LAN or the Internet.

In the example of FIG. 19, the mobile phone 1A captures still images(111A and 111B) and sends the still image data over the network 120 tothe PDA 91 for storage into an internal storage unit of the latter. Themobile phone 1B captures moving images and transmits the moving imagedata over the network 120 to the PDA 91. A moving image 112corresponding to the moving image data is displayed on the display unitof the PDA 91. The PDA 91 delivers to the mobile phone 1B over thenetwork 120 the still images 111A and 111B which have been acquired fromthe mobile phone 1A and kept in the internal storage unit of the PDA 91.The mobile phone 1B can thus verify the still images 111A and 111B sentfrom the mobile phone 1A to the PDA 91.

The processes carried out by the devices involved in the above exampleare discussed below with reference to the timing chart of FIG. 20.

Initially, the mobile phone 1B in step S181 sets the high-quality modefor the capture of moving images. In step S182, the mobile phone 1Bstarts generating and transferring moving image data. In keeping withstep S182, the PDA 91 in step S171 starts receiving the moving imagedata transferred from the mobile phone 1B.

In step S161, the mobile phone 1A performs an imaging process togenerate still image data. In step S162, the mobile phone 1A startstransferring the still image data. In conjunction with step S162, thePDA 91 in step S172 starts receiving the still image data transferredfrom the mobile phone 1A.

After starting to receive the still image data in step S172, the PDA 91reaches step S173 and signals to the mobile phone 1B the start of stillimage data reception. The mobile phone 1B receiving the signal in stepS183 goes to step S184 to set the low-quality mode for the capture ofmoving image data. Thereafter, the mobile phone 1B generates a reducedamount of moving image data representing low-quality moving images, andtransfers the generated data to the PDA 91.

In step S174, the PDA 91 starts delivering the received still image datato the mobile phone 1B. In conjunction with step S174, the mobile phone1B starts receiving the still image data from the PDA 91 in step S185.

After transferring all the still image data to the PDA 91, the mobilephone 1A reaches step S163 to terminate the still image data transferand notifies the PDA 91 thereof.

Upon receiving the notice in step S175, the PDA 91 goes to step S176. Instep S176, the PDA 91 signals to the mobile phone 1B that the stillimage data reception has ended. The mobile phone 1B receives the signalin step S186.

After delivering all the still image data to the mobile phone 1B, thePDA 91 goes to step S177 to terminate the still image data delivery andnotifies the mobile phone 1B thereof.

Upon receiving the notice in step S187, the mobile phone 1B, alreadygiven the signal in step S186, determines that the traffic on thenetwork 120 has dropped and goes to step S188. In step S188, the mobilephone 1B sets the high-quality mode for the capture of moving imagedata.

In the manner described above, the mobile phone 1B can supply an optimumamount of moving image data to the PDA 91.

In the examples above, the mobile phone 1 was shown utilizing a CCD asits imaging device. However, the invention is not limited to this.Alternatively, a CMOS (complementary metal oxide semiconductor) sensormay be used in place of the CCD.

FIG. 21 depicts a typical structure of the CMOS sensor.

As shown in FIG. 21, the CMOS sensor may include three rows and threecolumns of pixels 121-11 through 121-33 having photoelectric conversionelements such as photodiodes, amplifier MOS (metal oxide semiconductor)transistors for reading and amplifying accumulated electrical chargesfrom the elements, and selector MOS transistors for activating theamplifier MOS transistors.

The pixels 121-11 through 121-33 are connected to vertical output lines124-1 through 124-3 (Vsig). The vertical output lines receive electricalcharges that are output from the pixels on the horizontal line selectedby control signals 123-1 through 123-3 (VSEL) issued by a vertical shiftregister 122. As with the CCD 12 explained earlier with reference toFIGS. 1 through 3, the vertical shift register 122 operates undercontrol of the V driver 52 outside the CMOS sensor to output the controlsignals 123-1 through 123-3 (VSEL).

The electrical charges output onto the vertical output lines perhorizontal line are accumulated in storage units 125-1 through 125-3having cumulative capacitors. When any one of switches 126-1 through126-3 is selectively activated by a control signal from a horizontalshift register 127, the electrical charge accumulated in the storageunit connected to the activated switch is read out onto an output lineVH and supplied to an integrator 128. As in the case of the CCD 12discussed with reference to FIGS. 1 through 3, the horizontal shiftregister 127 operates under control of the TG 51 outside the CMOS sensorto supply the control signal to the switches 126-1 through 126-3.

In the above setup, the CPU 31, as with the CCD 12, controls thevertical shift register 122 and horizontal shift register 127 of theCMOS sensor by means of the TG 51 and V driver 52. In so doing, the CPU31 can select the pixels from which to retrieve electrical charges inaccordance with the currently established mode for the capture of movingimage data.

That is, as shown in FIG. 22, the CPU 31 selects the pixels from whichto extract electrical charges at suitable intervals (e.g., from thepixels marked by circles in FIG. 22) in a CMOS sensor having pixelscorresponding to R, G or B arranged in the Bayer pattern as in the caseof the CCD 12 shown in FIG. 9. In this manner, the amount of generatedimage data can be selectively reduced.

The structure above allows the CPU 31 to set a suitable moving imagecapture mode based on the communication speed and on a request from thecommunicating party, as in the case of the CCD 12. It is then possibleto generate moving image data in quantities commensurate with the modethus established, whereby a suitable amount of moving image data issupplied.

In the example above, the CMOS sensor was shown having pixels orphoto-registers 121-11 through 121-33 in three rows and three columns.However, the invention is not limited to this arrangement. Thus, anynumber of photo-registers may be furnished as needed.

As described, the mobile phone 1 according to the invention controls theamount of moving image data to be transferred to another communicatingapparatus in accordance with diverse external and internal factors. Theexternal factors include the communication capability of the otherapparatus and the bandwidth and traffic status of the network via whichthe two apparatuses are connected. The internal factors includetransmission or reception of still images executed by the imaging deviceof the invention during the transmission of moving images. Under suchcontrol of the mobile phone 1, an optimum amount of moving image datacan be supplied to the other communicating apparatus.

The amount of moving image data may be determined either by apredetermined program or in consideration of the transmission speed atwhich the image data are transmitted and the bandwidth currently ineffect for the network. Where the amount of data is to be determined bya predetermined program, that program may be arranged to read all pixelsin USB-based communication or to read part of the pixels in wirelesscommunication. Where the transmission speed and bandwidth are to beconsidered, available bands on the network may be monitored byperiodically transmitting a PING packet or the like to the othercommunicating apparatus in order to measure the time required forresponses to be returned therefrom. The available bands thus monitoredand the communication speed found currently in effect are utilized as abasis for determining the compression rate, i.e., a rate of optimaldiscrete reduction.

Other factors than those outlined above may also be used for controllingthe amount of image data to be transferred. For example, the load on theCPU 31 in the mobile phone 1 may be factored in for control purposes.

Although a mobile phone 1 furnished with a camera function was mainlyexplained in the foregoing description, the invention is not limited tothis. Any other suitable electronic device may take the place of themobile phone 1, such as a PDA or a personal computer with a camerafacility, or a communication-capable digital camera.

Although the mobile phone 1 was described as having two communicationfacilities, i.e., USB controller 40 and wireless communication unit 42,the invention is not limited to such arrangements. Thus, the mobilephone 1 may have only one suitable communication facility or three ormore communication facilities.

These communication facilities may be designed for wired or wirelesscommunication. The communication protocol used for wired communicationis not limited to USB; the protocol may be that of IEEE 1394, SCSI,Ethernet(R)-based IEEE 802.3, or some other suitable standard. Wirelesscommunication may be implemented not only through a carrier overtelephone lines but also in the form of short-distance wireless linkssuch as those of IEEE 802.11x, Bluetooth, or infrared-based IrDa.

In the foregoing description, the PDA 91 was shown as the apparatus thatseeks to acquire moving image data. However, the invention is notlimited to this. Any one of diverse types of electronic apparatuses,such as mobile phones, digital video cameras and TV sets, may be adoptedas the device for acquiring the moving image data.

Although a plurality of conditions for the mode setting process werediscussed separately in the foregoing description, the invention is notlimited to this. That is, the multiple conditions may be appliedsimultaneously in combination as a basis for setting the mode.

The series of processes or steps described above may be executed eitherby hardware or by software. For the software-based processing to takeplace, programs constituting the software may be either incorporatedbeforehand in the dedicated hardware of a computer or installed upon usefrom a suitable storage medium into a general-purpose personal computeror like equipment capable of executing diverse functions.

The storage medium that accommodates computer-executable programs to beinstalled into the computer may be provided in the form of a packagemedium, such as the magnetic disc 44 (including flexible discs), opticaldisc 45 (including CD-ROM (compact disc-read only memory) and DVD(digital versatile disc)), magneto-optical disc 46 (including MD(Mini-disc; registered trademark)), or semiconductor memory 47; or inthe form of the ROM 32 or flash memory 35 where the programs are storedtemporarily or permanently. The programs may be recorded to the storagemedium through diverse communication interfaces, such as routers andmodems, or via wired or wireless communication media including networks,such as public switched telephone networks, local area networks, theInternet, or digital satellite broadcasting networks.

In this specification, the steps which are stored on the storage mediumand which describe the programs to be executed by the computer representnot only processes that are carried out in the depicted sequence (i.e.,on a time series basis), but also processes that may be performed inparallel or individually.

As described, the inventive apparatus operated as per the inventivemethod supplies moving image data to another apparatus in which it is incommunication, feeding more specifically an optimum amount of image datato the latter. The apparatus of the invention controls the amount ofmoving image data to be transferred to the other apparatus in accordancewith diverse external and internal factors, the external factorsincluding the communication capability of the other apparatus and thebandwidth and traffic status of the network via which the twoapparatuses are connected, and the internal factors including thetransmission or reception of still images by the imaging device of theinvention during the transmission of moving images. In this manner, theinventive apparatus can supply an optimum amount of moving image data tothe other communicating apparatus.

1. An imaging apparatus, comprising: imaging means for capturing imagedata of an object; transmitting means for transmitting the capturedimage data to a communication device via a network; and adjusting meansfor adjusting an amount of the image data captured by said imaging meansbased on a communication speed at which the captured image data aretransmitted by said transmitting means.
 2. An imaging apparatusaccording to claim 1, further comprising: a plurality of units of saidtransmitting means; and selecting means for selecting any one of saidplurality of units of said transmitting means; wherein said adjustingmeans adjusts the amount of the image data captured by said imagingmeans based on the communication speed at which the captured image dataare transmitted by the unit of said transmitting means selected by saidselecting means.
 3. An imaging apparatus according to claim 1, whereinsaid transmitting means further transmits data other than the capturedimage data; and said adjusting means reduces the amount of the imagedata captured by said imaging means when said transmitting meanstransmits the other data.
 4. An imaging method, comprising: capturecapturing image data of an object; transmitting the captured image datato a communication device via a network; and adjusting an amount of theimage data captured in the capturing step based on a communication speedat which the captured image data are transmitted in the transmittingstep.
 5. An imaging method according to claim 4, further comprisingselecting any one of a plurality of transmitting units for transmittingthe captured image data wherein the transmitting step includescontrolling the transmission so that the captured image data istransmitted by the selected transmission unit; and the adjusting stepadjusts the amount of the image data captured in the capturing stepbased on the communication speed at which the captured image data aretransmitted by the selected transmission unit.
 6. An imaging methodaccording to claim 4, wherein the transmitting step further includestransmitting data other than the captured image data; and the adjustingstep reduces the amount of the image data captured in the capturing stepwhen the transmitting step transmits the other data.
 7. An imagingapparatus, comprising: imaging means for capturing image data of anobject; compressing means for compressing the captured image data;transmitting means for transmitting the compressed image data to acommunication device via a network and adjusting means for adjusting acompression rate for compressing the captured image data based on acommunication speed at which the compressed image data are transmittedby said transmitting means.
 8. An imaging apparatus according to claim7, further comprising: a plurality of units of said transmitting means;and selecting means for selecting any one of said plurality of units ofsaid transmitting means; wherein said adjusting means adjusts thecompression rate based on the communication speed at which thecompressed image data are transmitted by the unit of said transmittingmeans selected by said selecting means.
 9. An imaging apparatusaccording to claim 7, wherein said transmitting means further transmitsdata other than the compressed image data; and said adjusting meansraises the compression rate when said transmitting means transmits theother data.
 10. An imaging method, comprising: capturing image data ofan object; compressing the captured image data; transmitting thecompressed image data to a communication device via a network andadjusting a compression rate for compressing the captured image databased on a communication speed at which the compressed image data aretransmitted in the transmitting step.
 11. An imaging method according toclaim 10, further comprising selecting any one of a plurality oftransmitting units for transmitting the compressed image data, whereinthe transmitting step includes controlling the transmission so that thecompressed image data is transmitted by the selected transmission unit;and the adjusting step adjusts the compression rate based on thecommunication speed at which the compressed image data are transmittedby the selected transmission unit.
 12. An imaging method according toclaim 10, wherein said the transmitting step further includestransmitting data other than the compressed image data; and theadjusting step raises the compression rate when the transmitting steptransmits the other data.
 13. An imaging apparatus, comprising: imagingmeans for capturing image data of an object; compressing means forcompressing the captured image data; transmitting means for transmittingthe compressed image data to a communication device via a network; andadjusting means for adjusting an amount of the image data captured bysaid imaging means and a compression rate for compressing the capturedimage data based on a communication speed at which the compressed imagedata are transmitted by said transmitting means.
 14. An imagingapparatus according to claim 13, further comprising: a plurality ofunits of said transmitting means; and selecting means for selecting anyone of said plurality of units of said transmitting means; wherein saidadjusting means adjusts the amount of the image data captured by saidimaging means and the compression rate based on the communication speedat which the compressed image data are transmitted by the unit of saidtransmitting means selected by said selecting means.
 15. An imagingapparatus according to claim 13, wherein said transmitting means furthertransmits data other than the compressed image data; and said adjustingmeans reduces the amount of the image data captured by said imagingmeans while raising the compression rate when said transmitting meanstransmits the other data.
 16. An imaging method, comprising: capturecapturing image data of an object; compressing the captured image data;transmitting the compressed image data to a communication device via anetwork; and adjusting an amount of the image data captured in thecapturing step and a compression rate for compressing the captured imagedata based on a communication speed at which the compressed image dataare transmitted in the transmitting step.
 17. An imaging methodaccording to claim 16, further comprising selecting any one of aplurality of transmitting units for transmitting the compressed imagedata; wherein the transmitting step includes controlling thetransmission so that the compressed image data is transmitted by theselected transmission unit; and the adjusting step adjusts the amount ofthe image data captured in the capturing step and the compression ratebased on the communication speed at which the compressed image data aretransmitted by the selected transmission unit.
 18. An imaging methodaccording to claim 16, wherein the transmitting step further includestransmitting data other than the compressed image data; and theadjusting step reduces the amount of the image data captured in thecapturing step while raising the compression rate when the transmittingstep transmits the other data.